A window keeps constant on my screen to restart the computer(norton), but when i last did it i couldnt get the computer back up.

Get rid of Norton. There are alot of Free Software Programs that are better.
Read on:

Go to www.trendmicro.com, and do the free scan Trend Micro's House Call virus, spyware and malware scanner and cleaner. http://housecall.trendmicro.com

If you have anything, remove them. Helpful Free Software below Read On.

FREE SPYWARE
Download Spybot Search & Destroy. Restart computer, then run Spybot to see what spyware comes up, AND DELET IT.

FYI---Virus Protection-- 2 programs of virus protection will conflict with each other and will actually cancel out the protection. SO just download one.

Running Spybot Search & Destroy with EITHER Avast or Avg (great Free virus protection programs ) will keep a computer in good working condition. FREE

Avira AntiVir – Free Anti-Virus Protection
http://www.free-av.com/

FROM MICROSOFT 2009 -Free --Security Essentials
http://www.microsoft.com

Pop up Blocker- free
www.panicware.com

Spybot - Search & Destroy 1.5.2 -FREE SPYWARE
http://www.download.com/Spybot-Search-De…

Avast- FREE ANTI VIRUS PROGRAM
http://www.avast.com/eng/home-registrati…

AVG- FREE SPYWARE PROGRAM
http://www.free.avg.com

Ccleaner- FREE
http://www.download.com/3120-20_4.html?q…

Malware- FREE
http://www.malwarebytes.org/.

$ *** KASPERSKY ***
http://www.kaspersky.com

There are alot of $ anti-virus and Internet security programs out there-ie: Norton, McAfee, Panda, Bitdefender. If you would like to pay $ then get ***Kaspersky***-- 2010 , I feel that is the best for your money.

REMEMBER TO KEEP UP THE DAILY MAINTENANCE ON ALL OF YOUR COMPUTERS.!

If all else fails, then do a Reformat. You will loose everything, so do a Back-up.

Good Luck.