'sup peops!
I use a DEll Inspiron E1505 n i've had it 4 ova a year now. Problem is i keep getting a prompt message saying ", can't find bootable device n asking me to press F5 to try reboot, "weneva i put it on.
It persisted 4 some time, stoped only to resume again. I've made d following observations though:
*the hardrive seems to be detachable as there's no screw attached to it thus can be removed n fixed again;
*the prompt message mainly comes on after i've moved my system from one place to another n the hard drive's position appears to have been altered;
*the prompt message stops once i readjust d harddrive and then turn on d system again.
I don't know if anyone's had d problem before and i'd like an intervention before a crash of some sort occurs.
S.O.S, !

You said yourself buddie, it happens when you move your system, I think you should look for a screw and screw the harddrive so it wont move.
That I think is the solution to your problem. Do that and lets see what happens.
Hard drives should not move around, it can even spoil your IDE cable.