does cs5 support hd video

Adobe Premiere CS5 does support for HD Video. 

"there are no HD setting when i open a project"

Are you talking about the sequence settings?  If you are, what kind of footage are you using?  XDCAM, H264, AVCHD, etc.

"when i open footage it lags alot any way to fix this?"

What are you computer specs?  Windows or Mac, Processor, RAID, RAM, etc

I have a rather old system but when I use PPRO 5, it plays footage back rather good.

Wat that ONLY Premiere Pro, or did you buy a multi-product suite... and did you install EVERYTHING on all discs?

More information needed for someone to help... click these links and provided the requested information

-http://forums.adobe.com/message/4200840

-http://forums.adobe.com/thread/416679

This is what you do:

Deactivate

Uninstall

Run Cleaner Tool

Reinstall.

Adobe CLEANER Tool

>downloaded version of just premiere cs5 not a creative suite

There are TWO downloads... the program and the extra content

Did you download and install BOTH parts?

>what does the adobe cleaner tool do?

Click the link Ann provided and read