System Restore Does Not Work. Do I Need To Reinstall?

Hi,

 

I usually keep my computer on all the time. I recently came home and the power on my computer was off. I had a power failure. When I turned the computer on, Windows XP Home Edition came up very slow. I am unable to connect to the internet. When I go to the control panel and to network connections it is empty. I have a cable connection. I also cannot open any applications on my desktop such as my virus scanner (McAfee) or Windows Media Player. I get a message that the memory is too low. (512 ram). When I try to do a System Restore is says not available, try to restart and try to restore again. This never works. I had power failures before but they have never affected my computer like this. I have the computer and accessories attached to a surge protector and that is ok.

 

Could it be that my Widows XP is corrupted?  When I look at the task manager there are also no users listed wheras it use to be two. When I check the properties on My Computer the CPU is no longer listed with the memory amount.  I have run the Dell Diagnostics and it says all the hardware is ok.

 

Can someone please help and lead me in the right direction. I am a computer novice so I really have no clue.

 

Thanks in Advance!!