Problems with connecting

I will try to make this clear.
I switched from att to comcast 2 months ago, every day when I start the computer I have to power cycle the modem. Some days it says no connection, sometimes it says I am connected, but I am not.

My Att service had the modem and router in one box. Comcast didn't come with a router.

My first week of comcast I was getting half the internet speed advertised, I then turned on my att router and my speeds picked up to what they should be but I was still having connection problems

So another question I have
My comcast modem is wired, but it is wired through my att router, so I wonder why I am connecting wireless?
If I was connecting through the modem, I would think my speeds would have been normal


Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Core(TM) i5-2320 CPU @ 3.00GHz, Intel64 Family 6 Model 42 Stepping 7
Processor Count: 4
RAM: 6056 Mb
Graphics Card: Intel(R) HD Graphics, -1988 Mb
Hard Drives: C: Total - 935859 MB, Free - 751301 MB; F: Total - 953634 MB, Free - 518899 MB; H: Total - 2861585 MB, Free - 1445973 MB;
Motherboard: Dell Inc., 0GDG8Y
Antivirus: avast! Internet Security, Updated and Enabled