I've got some system restore information inside its directory on one of my drives. Since the service is disabled on my machine now, I assume its some leftovers from previous installations.

I tried to erase them and I can't. Tried to enable and disable the service (which usually deletes it) and no luck.

Since it's a system directory I can't erase that from there either.

Is there any trick or tool to erase these points??

To delete all but the most recent Restore Point

Start -> Run and type cleanmgr

Select Drive C: and then select more options on the Disk Cleanup for C: requester.

Use the System Restore -> Clean up tab to clear all but the most recent restore point.

To delete all of the Restore Points

Start -> Run and type sysdm.cpl now click the System Restore Tab

Turn Off System Restore on all drives. Click apply and then reboot. Go back and enable System Restore.

To reduce the no. of Restore points (FIFO)

Click the Settings tab and use the slider to drop back to about 5% to purge the oldest restore points. Do this on all drives.

Remember to reset to max after the reboot.

From this page.

If those don't work, boot off of a Windows PE or Linux cd and mount the drive and delete the folder.

Tried all and no luck.

What is exactly the process of using WinPE. I've got BartPE? is it good enough?

Can I Delete the "System Volume Infomrmation" folder?

Yeah, BartPE is fine. As for deleting that folder- if you want to be safe, just delete it's contents. If you like taking risks, delete the whole folder. It may destroy Windows, I can't remember

Well, I'll give it a try! destroying Windows sounds fun !!