Welcome to the forum.
Virtual Memory is HDD (Hard Disk Drive) space, that your OS uses when it has exhausted the installed RAM.
What OS, and what version of that OS do you have?
In Windows, it's called Windows Virtual Memory, or Page File. The Page File can be set to be automatically created and managed (so that it expands or shrinks, as is needed), and the maximum size can be specified - or, it can be set to be statically managed, where, upon bootup, it is created to the size defined in its settings. For video-editing, I like the statically managed Page File, as that saves CPU cycles, and it's always located on my HDD in the same spot, and at the same size.
For a 32-bit Windows OS, I use a size factor of 2.5x the amount of installed RAM. With my 32-bit systems, I have the full 4GB of RAM, so I set my Page File to be sized at 10GB. For a 64-bit OS w/ 12-32GB of RAM, the Page File will be used less often, and the factor can be decreased to perhaps 1x the installed RAM.
Along with your OS details, please tell us the amount of installed RAM.
As the exact location to set the Page File (if you are on Windows) differs slightly OS version to version, it would be best to know what you have, before anyone starts trying to direct you to how to adjust the settings.
Good luck, and let us know just a bit more please,
Thanks for helping me. (does the info below answer your questions?
OS Name Microsoft Windows 7 Home Premium
Version 6.1.7601 Service Pack 1 Build 7601
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name OWNER-PC
System Manufacturer Gateway
System Model NV53A
System Type X86-based PC
Processor AMD Athlon(tm) II P320 Dual-Core Processor, 2100 Mhz, 2
Core(s), 2 Logical Processor(s)
BIOS Version/Date Gateway V1.05, 5/11/2010
SMBIOS Version 2.6
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume2
Locale United States
Hardware Abstraction Layer Version = "6.1.7601.17514"
User Name Owner-PC\Owner
Time Zone Canada Central Standard Time
Installed Physical Memory (RAM) 4.00 GB
Total Physical Memory 3.49 GB
Available Physical Memory 1.31 GB
Total Virtual Memory 6.99 GB
Available Virtual Memory 1.55 GB
Page File Space 3.49 GB
Page File C:\pagefile.sys
Sales and Marketing
That tells us nearly everything. Your Windows Virtual Memory/Page File is set to ~ 1x the size of your installed RAM. For a 32-bit OS, which can only access ~ 3.5GB RAM (out of the installed 4GB), and for video editing, I would go to Control Panel>System>Advanced>Performance>Settings>Advanced>Virtual Memory and click on Change. For Initial Saize, I would choose 4096 and Maximum Size 8192. Activate the Custom Size radio button. Then OK out of those dialog screens, shut down the computer completely. Then, restart the computer. It might take a moment longer to boot up, as Windows will need to create the new Page File.
Personally, before doing the Page File size change, I would definitely do a fresh defragmentation of the HDD. I would also check that I have adequate free-space on my HDD. I recommend a minimum of ~ 60GB to effectively use PrE for editing video.
I notice that you have a sig (possibly added via your e-mail client, or similar), with personal information in it. As these are open forums, you might think about removing that personal info. As I had already replied to your post, you will not be able to go back and edit (I should have seen that, and replied to your original post), but if you give me permission, I can delete that for you. While 99.9% of the subscribers here are great people, anyone has access to this forum, and who knows what that other 0.01% is thinking? Same for any e-mail addresses, that people often include - spambots creep around this forum, just looking for e-mail addresses, to send spam to.
Let me know, and I will edit that material out for you.