I don't know how you turn off the screen but the manual might tell you that - http://cdgenp01.csd.toshiba.com/content/suppo...0_THRiVE-AT100_052011.pdf

However if you want to have the tablet compute while the screen is lit, you can do that by going to 'preferences.'

When you bring up the boinc app, in the upper left next to the boinc logo you will see 3 horizontal bars.

Tap on that, then preferences.

Under general, there will be an option to 'pause computation when screen is on'. that is checked by default - uncheck it.

If you don't see the option, then check the box that says 'show advanced preferences and controls.' That is UN-checked by default.

good luck

Your screen doesn't turn off ever? I bet that really sucks battery. That feature was made default, since many devices will not make very much headway on their charge cycle if the processor is going at full-bore along with the screen on. As it stands, a lot of devices have trouble charging running BOINC with the screen off, though there are ways to overcome that limitation.

But, as pointed out--you can disable that in the advanced preferences.