Ahem... System Restore... Start -> Accessories -> System Tools -> System Restore. This will only revert settings, which seems to be your issue, and will not tamper with files. I suggest doing this ASAP. Also, because you say you don't know computers well, here's how it goes. Once you go to system restore, click on the dot next to "restore to an earlier time". Click Next. You will see a calendar. Pick the day and time. Make sure that you pick a time BEFORE the software was installed, so this will work. Click next. On this screen, make sure the date and time looks right, and click finish. The computer will now attempt to restart. You will see a progress meter just before it restarts. This bar may move rather slowly. Be patient. Once the computer restarts, things should be back to normal. Keep in touch.
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