Try going from the Line Out of the POD to the Line In of the laptop and see if you still get the clicks and pops.
If not then it is most likely an issue with the USB port on the laptop sharing it's IRQ with other devices. Laptops tend to share IRQ's, which is fine for normal computing. Yet when it comes to doing DAW work, this can be a real pain.
Unfortunately HP.com offers very little info as to detailed specs of that machine. Namely the chipset used. I did see an updated driver for the video, but that was about it. There have been issues with VIA based chipsets, but I'm uncertain about updates for a laptop (if it even uses a VIA chipset).
It wouldn't hurt to update the video driver, unless you have already done so.
I found it
here for Windows XP.
If you don't know how to check for IRQ sharing .... Navigate to control panel/system/hardware/device manager ... then click view and select to view resources by connection, then click the + sign next to interrupt request (IRQ).
The list will expand and you can then see what all, if any, IRQ's are being shared. Pay close attention to the USB Universal Host Controller and anything that it may be sharing with. If it is sharing with other devices, a workaround may be to add more USB ports via the PCMCIA slot. Though it is also possible that the PCMCIA slot will be sharing an IRQ also. Soundcard and video are two that you don't really want to have to share with. Other things such as modem or NIC aren't as bad ... as normally those devices wont be in use during any DAW work.
Wish I could be of more help with a simple fix, but like I said ... laptops can be a pain.
-Ken