I did not use it for about 10 days. Thereafter, when I switched it on, it started giving a long beep. I did a forced switch-off and switched on again. Once again a long beep, but after tapping a few keys at random it started up with a DOS screen, asking me to make a choice of system to start. I have Windows 7 and that was the only choice listed there. After I press 'Enter', Windows gets loaded and there is no problem for the whole session therafter.
This is the way it happens every time I switch on the Laptop.
In a couple of these instances, I also ran a Windows Diagnostic Tool, which ran a Test and declared 'No problem was noticed'.
I had read an advice elsewhere on similar problem that removing and re-fitting RAM module may help. I tried it, but it did not work.
I am sure somebody will be able to help me on this Forum - Thanks in anticipation!