Distro-hopping or multi-OS-booting sometimes results in a non-booting grub. You can use PCLinuxOS (or any other) LiveCD to restore grub in a safe way. Here are the steps:
1. Boot system from PCLinuxOS LiveCD
2. Open a terminal and be root user - enter "su"
3. Enter command "grub" (it will put you on grub> prompt)
4. Then locate grub files by: "find /boot/grub/stage1"
5. It will return grub locations (it may be (hd0,0) or (sd0,0))
6. As per the location of grub enter "root (hd0,0)" or "root (sd0,0)" or some other.
7. Then issue "setup (hd0)" or "setup (sd0)" or some other.
8. Finally enter "quit"
Now reboot the computer without LiveCD.
Note: Use commands without quotes.