Windows 7: Virus and Virtual Memory is Low

Uh, I've been having problems with my computer lately. It keeps running slowly lately and i keep getting a backdoor trojan that makes my taskmanager and regedit mess up. But i have norton and it always say it deletes it. Also I have problems with my Virtual Memory. Sometimes a box keep coming up asking me if I want to close prgrams to save some space. So how would I be able to fix this using paging file or something else?

It would help if you updated your system specs, but basically increasing virtual memory is only going to postpone the inevitable. If Norton is removing the trojan and it keeps coming back, either Norton is not actually completely removing the infection (likely) or you have an infected file or program you keep putting back on the machine (less likely, usually people are careful about the USB disks and CD/DVDs they put in their PC after an infection). I might suggest scanning your machine offline using a bootable virus scanner, and replacing Norton with a better (and free) A/V program like MS Security Essentials or Avast.

Bitdefender has a good (and free) bootable CD (ISO image download here) that you can use to clean your machine offline - instructions here (also includes USB key instructions if you wish to use that rather than a CD/DVD).

Woah.... Excuse me but i had like 366gb space yesterday! Now i have 46gb... Any ideas what is going on???

Maybe some virus is keep creating files/directories? Try to trace which folder has unexcepted size and see what files are there. Also try scanning your computer with few anti malware programs, not only with Norton.

Yea right now im using Malewarebytes because it fixed the taskmanager and regedit thingy last time.. But I searched in computer then program files and i dont see anything with any abnormal sizes. everything looks fine.. Anywhere else to look?

Do you have enabled option to show hidden files/directories?

You best set back to an earlier restore point or image. It is apparently difficult to fight that virus. If Norton does not do it, It is very unikely anothe AV program can deal with it. Norton is usually the very best option you have.

@ Diath, no i just enabled it. What to do now?

ok the malewarebytes i was using fixed the taskmanager problem buy my space is still messed up.. only have 50gb out of 400gb wen yesterday i had about 350gb...

WinDirStat will tell you what's on your disk - unless those are shadows. For those you have to run vssadmin list shadowstorage in cmd.