You know. I am really going to be mad; if I have to take this computer in for more space when I specially asked about upgrades and they said fine. Not good business practice being dishonest to customer.
The 4 GB is your RAM, not your disk space. Lion only requires 2 GB of RAM, so you're good there.
The 7 GB recommendation is for free hard drive space -- odds are you have that much available unless you've filled the whole hard drive. Open up Finder and do a "Get Info" on your hard drive under "Devices" -- that will tell you how much hard drive space you have available.
There are 2 primary types of memory (that the non-engineer, non-programmer, non-chip designer) really cares about.
RAM and the size of your hard drive. Many Macs come with at least 2 GB, and many come with much more. You ONLY need 2 GB; you have 7 GB.
Hard Drive - I don’t know how big a hard drive you bought with your Mac. Many Macs came with a 300 GB drive; is your drive 97% full? If not, then you have more than 7 GB free - and you should be fine.
If you pull up the info panel on your hard drive; you will know the hard drive capacity, how much space you are using, and the all-important ‘Free space available’.
If you have more than 7 GB of free space available - you are golden, good to go.
If you have less than 20 GB of free space, I personally urge you to invest in a second hard drive and move some stuff over. Hard drives never run at peak performance when they are over 80% full. I cannot speak to the performance/capacity ratio on the new SSD (solid-state disks) that are now the latest screaming storage media. I simply don’t have any experience with them, yet.
Unless you are a software/music pirate who has completely filled your hard drive with all that junk, it is doubtful you wouldn’t have at least 7GB of hard drive space free.
I’m trying to figure out why your posts have almost an angry tone to them - whats up with that?