As linney stated the event will be in the application log with a source of winlogon. Double click on the entry to get the details.
Here is an example of the details of a chkdsk that I did:
Event Type: Information
Event Source: Winlogon
Event Category: None
Event ID: 1001
Date: 7/25/08
Time: 1:23:08 AM
User: N/A
Computer: POSEIDON
Description:
Checking file system on C:
The type of the file system is NTFS.
Volume label is ACER.
A disk check has been scheduled.
Windows will now check the disk.
Windows has checked the file system and found no problems.
46532272 KB total disk space.
14884941 KB in 61192 files.
20512 KB in 5376 indexes.
0 KB in bad sectors.
150797 KB in use by the system.
65536 KB occupied by the log file.
31476021 KB available on disk.
512 bytes in each allocation unit.
93064544 total allocation units on disk.
62952043 allocation units available on disk.
Internal Info:
90 1a 01 00 13 04 01 00 0a 59 01 00 00 00 00 00 .........Y......
08 01 00 00 00 00 00 00 53 02 00 00 00 00 00 00 ........S.......
5e 0b 0b 09 00 00 00 00 a6 10 f2 24 00 00 00 00 ^..........$....
9e dd ea 0c 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 5c 71 1c 43 00 00 00 00 ........\q.C....
99 9e 36 00 00 00 00 00 10 3a 07 00 08 ef 00 00 ..6......:......
00 00 00 00 00 34 81 8c 03 00 00 00 00 15 00 00 .....4..........
Windows has finished checking your disk.
Please wait while your computer restarts.
For more information, see Help and Support Center at
Cheers.