I hope Generator's recommendaiton works but, to be honest, I have my doubts your problem is caused by a virus.
The "memory could not be written" issue is a very common problem with a seemingly wide variety of fixes.
For example, here is a thread on another site where I'm a member. Several suggestions / remedies for you to try .....
http://www.geekstogo.com/forum/memor...ten-t4911.html
Personally, before anything else, I would try a system restore to a time before the problem arose.
Good luck.
OJ