Acer Aspire 3620 memory parity error..Help!?

Hi There
I have an Acer Aspire 3620 laptop and In the last week I first started getting a pop up saying my virtual memory is to low and then any programs I had open would close. The computer also ran alot slower than usual. I have a 20 gig C drive and a 50 gig D Drive, both with a combined 23 gig of free space still remaining on them.
My boyfriend swaped my one gig of ram for two gig also. In the last 2 days a blue screen has come on saying i have a memory parity error and hardware failure and the only way to get out of the screen is to turn it off and on again. It will run again as normal for a little while but the message is starting to become more frequent.
Also, if this makes any sense it says the cpu memory is running at 100% which my boyfriend said isnt normal. I usually only have a couple of windows open at a time and mainly am browsing the net so not sure why this is happening. Is there something I can do to fix this problem? Thanks