How I can solve start-up issue in Windows Vista Home Premium?

Hi folks,
I have got a HP Pavilion Model# dv6700 notebook (Intel Pentium Dual CPU T2370, along with 3 Giga Memory). I have also installed Windows Vista Home Premium on it. But I am facing an issue with it's start-up. In-fact, it was probably performing an update automatically and now it won't start up anymore.
It usually gets to the screen where it says "Configuring updates etc: Stage 4 of 4 – 7% complete" please Do not turn off your computer. But there it hangs for almost 20-35 seconds, then no advancements in the 7%. After that, it just reboots automatically.
This really is a very strange and irritating issue for me because I haven’t experienced such type of issues before and have applied all my known methods to fix it, but all declared as just the waste of my time.
For the purpose of handling/overcoming this strange issue, I've tried starting my Windows from last known good configuration of the window first of all but via this, issue has not been fixed by me. I also tried running my operating system in safe mode but it didn’t work even in this case and just did the same thing as earlier.
Well, I think that I also have another option which is system restore, but I am afraid to take/choose it because it is not confirmed to me, that whether it would delete everything on my computer (like my documents,music or photos etc)? I just can say may be yes (that’s why I am not willing to choose the option of system restore).
Now, I must agree with the fact that I have got no further technical knowledge to solve this issue and that’s why I am asking for help from you dear.
Would you please like to tell me “How I can solve start-up issue in Windows Vista Home Premium?” I am waiting to get/learn decent technique about this specific problem, from your side.
Any suggestion would be appreciated by me.
Cheers,
