I have a crt monitor hp5500 and I am using win7 ultimate edition.
When I switch on my monitor it increases/decreases sometimes brightness or contrast all by itself as if someone is pressing the buttons on my monitor. The monitor becomes stable after about min 15min of use.
What could be the problem and how to rectify it.

P.S. I have attached a video of my monitor's strange behavior.

Your video did not get attached. You might want to upload it to photobucket and give a link so we can watch it.

Sounds like normal start up monitor to me. Mine does the same thing. Starts sort of dark and then gets lighter as everything warms up. It's always done that for me.


Also your video card may need changed.

How old is your monitor?

The monitor is about 5yrs old.
The details of the system is as follows:

Computer:
Computer Type ACPI x86-based PC
Operating System Microsoft Windows 7 Ultimate
OS Service Pack -
Internet Explorer 8.0.7600.16385
DirectX DirectX 11.0


Motherboard:
CPU Type Intel Pentium 4, 2400 MHz (18 x 133)
Motherboard Name Hewlett-Packard HP d330 uT(DM202P)
Motherboard Chipset Intel Springdale-G i865G
System Memory 1399 MB (DDR SDRAM)
DIMM1: Hynix 256 MB PC3200 DDR SDRAM (3.0-3-3-8 @ 200 MHz) (2.5-3-3-7 @ 166 MHz)
DIMM2: Smart Modular SM5641635D8N6CLIBH 128 MB PC2700 DDR SDRAM (2.5-3-3-7 @ 166 MHz) (2.0-3-3-6 @ 133 MHz)
DIMM3: 1 GB PC3200 DDR SDRAM (3.0-3-3-8 @ 200 MHz) (2.5-3-3-7 @ 166 MHz)
BIOS Type Compaq (08/10/04)
Communication Port Communications Port (COM1)
Communication Port ECP Printer Port (LPT1)

Display:
Video Adapter Intel(R) 82865G Graphics Controller (96 MB)
3D Accelerator Intel Extreme Graphics 2
Monitor HP 5500 [15" CRT] (13331262039093)

Multimedia:
Audio Adapter Analog Devices AD1981B(L) @ Intel 82801EB ICH5 - AC'97 Audio Controller [A-2/A-3]

Storage:
IDE Controller Intel(R) 82801EB Ultra ATA Storage Controllers
IDE Controller Intel(R) 82801EB Ultra ATA Storage Controllers
Storage Controller MagicISO SCSI Host Controller
Disk Drive Disk drive (37 GB, IDE)
Disk Drive ST310212A ATA Device (10 GB, 5400 RPM, Ultra-ATA/66)
Optical Drive CD-ROM Drive
Optical Drive DTSoftBusCd01
Optical Drive MagicISO Virtual DVD-ROM0000
SMART Hard Disks Status OK

Partitions:
C: (NTFS) 25447 MB (5797 MB free)
D: (NTFS) 12614 MB (6551 MB free)
F: (NTFS) 9760 MB (2109 MB free)
Total Size 46.7 GB (14.1 GB free)

Input:
Keyboard Standard PS/2 Keyboard
Mouse HID-compliant mouse
Mouse PS/2 Compatible Mouse

Network:
Primary IP Address
Primary MAC Address
Network Adapter Broadcom NetXtreme Gigabit Ethernet
Modem Motorola SM56 Data Fax Modem

Peripherals:
USB1 Controller Intel 82801EB ICH5 - USB Controller [A-2/A-3]
USB1 Controller Intel 82801EB ICH5 - USB Controller [A-2/A-3]
USB1 Controller Intel 82801EB ICH5 - USB Controller [A-2/A-3]
USB2 Controller Intel 82801EB ICH5 - Enhanced USB2 Controller [A-2/A-3]
USB Device Audio_Device
USB Device USB Composite Device
USB Device USB Input Device
USB Device USB2.0_Camera

DMI:
DMI BIOS Vendor Hewlett-Packard
DMI BIOS Version 786B2 v2.43
DMI System Manufacturer Hewlett-Packard
DMI System Product HP d330 uT(DM202P)
DMI Chassis Type Tower

I have a Gateway monitor that I got with my PC back in 2002. It is an LED type and does the same thing. It always did this.