Do I have a virus? (See description)?

I'm experiencing three major problems on my computer, and I'm worried I might have a malicious program on my computer. I have a virus protection program (spy sweeper) but it's not up-to-date. If this description fits any known viruses, please let me know.

1. Whenever I click on a link to open a new window, it automatically opens a glitched window along with the linked one. Also, whenever I enter a link into the address bar, it opens it in a new window.

2. Task Manager has been disabled by ''the Administrator'' but there's only one account on this computer.

3. When shutting down, it says there's other users logged in, but like I said, I have the only account.

Do I have a virus? (See description)?hijackthis

first of all, spy sweeper is NOT virus protection. Its meant for spyware which is not a virus. So you machine is completely unprotected. You need to get virus software, update spy sweeper and run them and see if it will clear up your machine.

Do I have a virus? (See description)?malware

HI FRIEND,WHAT YOU DESCRIBED SOUNDS MORE LIKE A BLACKHAT HACKER THAT HAS WRITEN A BACK DOOR INTO YOUR OS THAN A VIRUS.WHAT IS A BLACKHAT?,A VERY SMART IT PERSON WHO LIKES TO TOY WITH OTHER PEOPLES SYSTEMS,HE HAS TURNED OFF YOUR TASK MANAGER TO WEAKEN THE 64 BIT NTFS-FILE SYSTEM,CREATED A FALSE ACCOUNT FOR WINDOWS BECAUSE HE IS USING YOUR MACHINE AS A SLAVE.DO YOU USE ADSL OR A OTHER FORM OF WIRELESS INTERNET?,IF SO DISCONNECT AND RESTART YOUR COMPUTER WHILE STILL NOT CONNECTED TO THE INTERNET AND SEE IF IT CONTINUES,IF YOUR COMPUTER IS FASTER AFTER THAT AND THE PROBLEMS GO AWAY THEN YOU HAD A VISIT FROM A BLACKHAT,INSTALL A FIREWALL AND ANTIVIRUS BEFORE CONNECTING AGAIN,IT WILL STOP THAT BLACKHAT IN HIS TRACKS!.BEST WISHES AND GOODLUCK,IT MANAGER SA
it's worth it to scan your computer, but before you do that, make sure you have a good anti virus and make sure your anti virus and windows are up to date.
use this online scan