After working on my computer (length of time does not matter), I will try to open a program like excel (it would be any program on my computer). I receive a message that the application cannot initialize. I must reboot my computer to get things working again. I have Trend Micro Virus and Spywaree 2008 and RegCure registry cleaner. I have done several scans and cannot find any malware, virus or other infection. I have run RegCure. There is no improvement in my computer. I have a Sony Vaio Windows XP Home SP2 with 1 gig of RAM. Any suggestions on what I can do to fix my computer?

UPDATE:

I replaced the RAM and now my computer is working fine.

Thanks for that update ,much appreciated.