Trouble starting Windows XP

Hi,
I have Win XP-1 SP3, My computer is EMachines T6520 It had been working well
for many months until about a week ago, when I tried to boot up and Windows
XP would not start. When I tried to start up, I got the eMachines opening
screen, A black screen with a big white E on it. That is the way it has
opened for a long while and it used to be quickly followed by the Windowx XP
opening screen. Now it gets stuck on the Emachines "E" screen
On that screen there's a brief line "F10=boot menu". I clicked on F10
and nothing happened. Since then I have done some experimenting ( read
"fooling around") and found that when I hit the F10 key and wait several
minutes, a boot menu does appear. It shows I am set to boot from the HD and
there are a couple of other choices. It says to select the proper one and
hit the F4 key. I did, using the HD setting, and it took a few minutes, but
eventually the Win XP opening screen appears and allows me to go on and use
the computer. That's how I'm able to rech this NG for suggestions.
I ran msconfig and checked the info there. It was set for "Normal Startup".
I set it for "Selected Startup" to see if that would help, but it did not.
Each time I try something like that , a reboot is required , then I have
to use the F10 procedure mentioned above, which takes about 10 minutes
before I'm able to be booted up. Sadly I don't have a "boot disk".
Some of the startups using the F10 method have changed my screen resolution
to 800x600 and I've had to set it back to 1280 X 1024.
Not sure if I'm leaving out any pertinent info about my setup. Any help
will be greatly appreciated.

Thanks, ... Fred