It sounds like your browser has been compromised. Do you have any issues logging onto other sites?

Regardless try the following -

1) Download the following programs to your desktop. Do NOT install them yet.

a)Ad Aware
b)Spybot S&D
c)Hijack This
d)ClamWin
e)CCleaner

2) Once all of these are downloaded reboot your computer and enter safe-mode. You get safe-mode by hitting the F8 key as the computer reboots. If you reach the part of the boot process where the lines are filling up across the bottom you waited to long. It's best to start tapping as soon as the screen goes blank. You'll see a menu with several choices in it, select "Safe mode with networking". It'll take a little longer than normal to boot into safemode, but once it does install the programs you downloaded.

3) After you install the programs update each one of them. It should be pretty self explanatory, but if not shoot me a pm and I'll baby step you through it.

4) Run all of the programs in the following order.
a) CCleaner - It cleans out temp files, empties trash, cleans out history, auto completions (like when you start to type in the browser)

b) Spybot S&D - Program to detect and remove adware, spyware, malware, browser hijacks, etc

c) Adaware - Same as Spybot S&D. They tend to compliment one another picking up things the other missed.

d) ClamWin - This is a virus scanner. Free, low impact on system performance and updated on a regular (usually daily basis)

5) Restart your computer normally. Meaning don't go into safe mode. Once it has restarted click start->run->type msconfig->ok. You'll get a window with several tabs on it, click "startup" then click disable all. Restart your computer. It should run much faster than normal during startup. By disabling all start up items you are preventing them from loading during system start, but keeping them on the pc so you can get to them by clicking their icon.

6) Finally run the program Hijack This that you downloaded. You just want to get a report to text file. Once you've done that PM it too me. There's no personally identifiable information contained in it. It's a list of running programs and process on your computer. Anything the other ones didn't detect this should and then you can take them on by themselves.

A final note, if you're like most people you probably have a virus scan program that you never use and is expired, never gets updated, etc. If that's the case get rid of it and use clamwin. If that's not the case and you have less than 4 months on the subscription get rid of it and use clamwin.

By the time all this is done you shouldn't have any problems getting into Myspace.

Good luck!