xampp on Windows 7 problems

Question

I installed xampp 1.7.7 on my computer on Windows 7 and it seems to be not working. the problems are:

1. I need to access the htdocs via "127.0.0.1" because localhost is not recognised. it says "oops localhost cant be found"
2. mysql status is deactivated but on the xampp control panel appears to be running. when I try to access the PHPmyadmin the message I get is "not responding or wrongly configured"
3. even if I get to run my PHP files via 127.0.0.1 the variables in my code don't get recognised, and the message I get is "notice: undefined index" etc

I've done my research and I installed xampp on the root C:\ drive.

any help would do.