New PC decided to go wrong, help!

I've had this new PC for a few months, and last night Vista wasn't working properly, and all the glassy Aero effects stopped working. Today I turn my PC on and I get to some black screen about some Gigabit ethernet adapter, and asking me to insert a disk to boot from.

I have no idea what's wrong, and I have a terrible feeling I'm going to need to reinstall Vista and lose everything. I inserted my Vista Premium CD and it loaded up, and I got to the repair my computer part, but no existing version of Vista shows up, so the manual that came with my PC told me to click on load drivers and find a repair tool. Only trouble is there's a bunch of small text files and folders but I have no idea what I should load to get it to repair.

I'm hoping someone here might know what is wrong or could offer some solutions. I'm going to phone technical support tommorrow, but I felt it's worth a shot trying here first. I'm really depressed atm as this is a new PC and cost me quite a bit.

Try tapping the f8 key as your computer boots up, and when it gets to a screen that lets you select "safe mode" go with that one.
If it gets that far, that is.
If you do get into safe mode, I would recommend backing up anything before you start trying to troubleshoot. Just incase it is a more serious issue.

As Wrath stated, press F8 to get to Safe Mode and select Last Known Good Configuration.