Recording level

Was recording some tracks thru the day. Left the computer, it went into sleep mode. When I came back to start computer with x2  there was a pop up about some instruments being silent or something (should of had a better look), so I closed x2 and restarted the computer. When I opened x2 and tried to record on a track, like any other time, I'm getting a level showing to record, but when I start to record, there's no reading of the recording taking place in the track or any recording happening when playback on that track. I can hear everything else I recorded earlier but now can't record on a track. This has really stumped me, frustrating also, I restarted everything again, went through the steps of setting up I/O like usual...not sure what the problem is...any suggestions?   

WDI, Thanks for your help. Yes, punch in was on and that was the problem, You offered the solution. Now I know... Can't believe how frustrating it can be at times and then find out that it's a simple oversight. Live and learn....