Try Newegg.com Buy a generation back... Socket 754 for a MB (the most current's a 939). That way, you get better than they stick in those gateway boxes for cheaper.
For a processor, I'd go AMD Athlon.
When you upgrade MB and processor, be sure the RAM you have will fit--also a new MB may not have the same power connectors as your old one.
Check Tigerdirect.com
You can get from build-your-own up to full systems and very competitive prices.
Get an AMD Athlon X2 dual core CPU. If funds are tight, get the 3800. You'll LOVE IT!!!
You may need new RAM if you buy a new board, so be sure to look for boards that take the same RAM. I would also consider adding a cheap video card, rather than using the onboard video. It really does make a difference in what you see.
I'm all set otherwise I would buy one of these newest nforce boards with video on board. Are you aware that many new motherboards require a 24 pin connector on your power supply? There are adapters for you on ebay. http://cgi.ebay.com/20-Pin-to-24-Pin-Power-Connector-Cable-ATX-Power-Supply_W0QQitemZ5836114562QQcategoryZ45342QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Your power supply is likely 20 pin connector
My new board is an MSI KT6V ( FSB 400/DDR 400 up to 2GB Memory/MSI CoreCell chip/AGP 8X (doubles graphics bandwith 2.1 GBs)/ A socket for AMD +1500 to +3200)
No graphic accelerator card if you want premium video graphics but for 50 to 70 bucks for it,couldn`t go wrong.
I'm all set otherwise I would buy one of these newest nforce boards with video on board ----> http://www.newegg.com/Product/ProductList.asp?Submit=GO&Range=1&bop=and&description=6100&InnerCata=22
Go to www.arstechnica.com and then go to guides and look at "budget box" to find their recommended m/b, processor (& memory).
So you have a Pentium 1.8 GHz? I would download sisoft sandra lite and see how your processor stacks up against say a 2800+ Athlon XP and 2800+ Athlon64-->> http://www.sisoftware.co.uk/index.html?dir=dload&location=sware_dl_3264&langx=en&a=
As far as I'm concerned it's not worth the upgrade to an athlon 2800+. But upgrading to a dual core processor is a meaningful upgrade. Will you give a meaningful boost.
2800+ Athlon XP and 2800+ Athlon64 are pretty much the same in performance
I'm not trying to sound smart alecky, but if you have to ask it would probably be best to have a professional install it for you. You would have to reinstall Windows when you change the motherboard and that, frankly, isn't a simple procedure.
That is the best advice I can provide in a post. Good luck.
And Merry Christmas.
Anand Tech guide for budget system with video onboard
http://www.anandtech.com/guides/showdoc.aspx?i=2563&p=2
Lian Li case.
FSP Group AX500ATTX 500W Power Supply.
Western Digital Raptor 10K rpm SATA HDs.
LaCie 16x d2 USB2/Firewire Doublelayer DVD +/- RW Drive
Abit Fatal1ty AA8XE Intel Motherboard w/ 925XE Chipset.
Abit Fatal1ty X800XL PCI Express Graphics Card w/512 MB RAM onboard.
Intel Plentium 4 650 Prescott 3.4GHz 800FSB 2MG Cache socket 775 processor.
4GB Geil DDR2-533 PC4300 Memory.
9 case fans, 1 Intel cpu & 2 chipset OTES Ramflow, and 2 memstick fans, temp., power, and rpm controlled from Abit uGuru software.
It overclocks to 5.3 GHz on Half Life 2 without liquid cooling. The case LEDs are for fun.
An AMD setup will save a few bucks, with slightly less performance.
I went with a game setup, because if a kid can't break it, it will last a long time.
Get a whole new box and everything. The old boxes pile up, but as tech changes they become gradually incompatible. Also, with a new box comes a new OS. That alone is worth the trouble of upgrading the hardware. Keyboard, mouse, monitor, speakers, etc. can be kept--the box alone [with new boards, I/O ports, modem, network port] isn't real expensive.
The best site for reviews and ratings of online computer and electronics vendors is ResellerRatings.com. Whether building my own computer from components, or buying a laptop or digital camera, I go here first to find the vendors with the best service and prices.Ratings for some of the websites noted above:
I urge you to stick with online retailers that have plenty of reviews and a high rating on ResellerRatings.com. Both Newegg.com and ZipZoomFly are excellent. I would avoid the others listed above with low or few (none!) ratings.
Newegg.com 9.32 Tiger Direct 5.44 Office Depot 4.11 ZipZoomFly 8.20 BuyDirectPC none
If your power supply is not one of the top rated brands, such as Antec, Thermaltake, or the gold standard PC Power and Cooling, then junk it and get a decent one.
The key decision will be whether or not you want to play serious games. A gaming box (such as someone else posted above) will cost you twice a general purpose (office, web, documents, photos, email, ...) box. Last year, when I was building several PC's, I could outfit a general purpose box for about $500 in parts, or a gaming box for $1000 and up, in parts.
Your best bet, in my experience, if you don't want to custom build your own PC from all the parts, is to go to a site such as Monarch Computer Systems (rating 8.99) and pick something from their lists of either prebuilt, ready to go, or their built to order according to your selections.
I'd be tempted to go with Socket 939 AMD. The systems I built last year used that, so it is no longer bleeding edge at all. They provide good value for the money, or if you want more processing power, AMD is currently ahead of Intel in dual core performance.
Get plenty of memory (RAM), at least one Gigabyte for Windows XP. Too little RAM is the single biggest cause of "poor performance" complaints.
Even on the systems that I only use for editing text documents, I have given up on the onboard video and added a separate video card. The onboard video quality sucks, too blurry.
If you a spendthrift, wait until January or February, and pick up models that are being discontinued. Unless you know what you're doing, however, it is difficult to ensure you get good stuff this way.