Dual boot install issue

So, I dual boot Windows XP SP3 and OpenSuse 11.0 with Gnome, using GRUB as my bootmanager. When I first installed OpenSUSE about a month ago, I had no problems dual-booting; however, now whenever I start my Sony VAIO laptop up, I seem to always get “Operating System Not Found”. I will repeatedly turn off and on my laptop until I eventually get to GRUB, but this process sometimes takes up to 5-10 minutes and is starting to get a bit annoying. It started slowly, with the message only appearing once in awhile and going away after one to two restarts, but its has progressively gotten a lot worse. Any help at all to ensure that when I start up my computer I get to the GRUB menu would be incredibly appreciated, but please keep in mind I have only been using Linux for about a month or so.

A bit about my setup: Installed from the GNOME live CD after the DVD installer continually failed (possibly something to do with my DVD drive). VAIO is a VGN-FS660/W if it helps, with a Centrino processor. Again, dual-booting Windows XP SP3 and OpenSUSE 11.0 with GNOME.

This does not sound like a grub problem at all. More like a dickey connection to your HD.

Also suggest you run memcheck

my machine vaio-a517 hold after grub stage1. grub read only mbr and than stop! what can i do ?