Monitor Display-Gray Lines/Colors

Hi,
Not sure if this is a software or hardware issue but my monitor recently
began showing light gray lines across the screen. At the same time, the
colors are all slightly off.

Around the same time, my antivirus software (Trend Micro PC-Cillin Internet
Security 2007) reported a bad website and said it had to revert to the last
known good version of itself. Ran a ton of antivirus, adware and spyware
scans and didn't show any viruses although there were a few
critical/negligible objects in the adware scans that I had removed.

There are also some errors that showed up in the event log on the same day:
1)
0000: 41 70 70 6c 69 63 61 74 Applicat
0008: 69 6f 6e 20 46 61 69 6c ion Fail
0010: 75 72 65 20 20 50 63 53 ure PcS
0018: 63 6e 53 72 76 2e 65 78 cnSrv.ex
0020: 65 20 31 35 2e 30 2e 30 e 15.0.0
0028: 2e 31 33 32 39 20 69 6e .1329 in
0030: 20 75 6e 6b 6e 6f 77 6e unknown
0038: 20 30 2e 30 2e 30 2e 30 0.0.0.0
0040: 20 61 74 20 6f 66 66 73 at offs
0048: 65 74 20 30 30 30 30 30 et 00000
0050: 30 30 30 000
2)
0000: 41 70 70 6c 69 63 61 74 Applicat
0008: 69 6f 6e 20 46 61 69 6c ion Fail
0010: 75 72 65 20 20 70 63 63 ure pcc
0018: 76 73 63 61 6e 2e 65 78 vscan.ex
0020: 65 20 31 35 2e 30 2e 30 e 15.0.0
0028: 2e 31 33 32 39 20 69 6e .1329 in
0030: 20 75 6e 6b 6e 6f 77 6e unknown
0038: 20 30 2e 30 2e 30 2e 30 0.0.0.0
0040: 20 61 74 20 6f 66 66 73 at offs
0048: 65 74 20 30 31 37 33 39 et 01739
0050: 36 66 36 0d 0a 6f6..
3)
0000: 41 70 70 6c 69 63 61 74 Applicat
0008: 69 6f 6e 20 46 61 69 6c ion Fail
0010: 75 72 65 20 20 50 63 53 ure PcS
0018: 63 6e 53 72 76 2e 65 78 cnSrv.ex
0020: 65 20 31 35 2e 30 2e 30 e 15.0.0
0028: 2e 31 33 32 39 20 69 6e .1329 in
0030: 20 75 6e 6b 6e 6f 77 6e unknown
0038: 20 30 2e 30 2e 30 2e 30 0.0.0.0
0040: 20 61 74 20 6f 66 66 73 at offs
0048: 65 74 20 30 30 30 30 30 et 00000
0050: 30 30 30 000
4)
WMI Adapter-Open of service failed.

2 new errors showed up in the last couple of days:

1) Failed extract of third partyroot list at auto update cab: microsoft

2) NVIEW: WINWORD: WAITTIMEOUT

Sorry if that's too much (or not enough) info.

I'm running Win XP SP2 on an old Dell Dimension 4100 computer. Display
adapter is an NVIDIA Gforce2 MX/MX400. Monitor is a Lextron 19" flat panel
plug and play; tried using another old monitor I have-no change. I tried
system restore-no change. Tried rolling back/updating device drivers-no
change or no better drivers found (admitedly, I don't know if I've checked
all applicable drivers correctly). Also, uninstalled PC-Cillin and am now
using Comcast's free McAfee. Checked the graphics card and cable
coonections-all secure but still no change. Also blew out some dust from the
inside the tower. Any help would be greatly appreciated. Thanks!

Mike