Unable to download programs

I have a new Inspiron Model N5110 using Windows 7.

Suddenly today I am unable to perform any downloads. For example:

1. When I try to download Google Chrome I get this message

Below is a summary of the errors, details of these errors are listed later in the log.
* Activation of http://dl.google.com/update2/1.3.21.99/GoogleInstaller_en.application?appguid%3D%7B8A69D345-D564-463C-AFF1-A69D9E530F96%7D%26iid%3D%7B7FA73DB6-ED03-D6C1-45AB-F52270CB3208%7D%26lang%3Den%26browser%3D2%26usagestats%3D1%26appname%3DGoogle%2520Chrome%26needsadmin%3Dfalse%26brand%3DCHFX%26installdataindex%3Ddefaultbrowser resulted in exception. Following failure messages were detected:
+ The system cannot find the file specified. (Exception from HRESULT: 0x80070002)

COMPONENT STORE TRANSACTION FAILURE SUMMARY
No transaction error was detected.

WARNINGS
There were no warnings during this operation.

OPERATION PROGRESS STATUS
* [3/7/2012 5:31:45 PM] : Activation of http://dl.google.com/update2/1.3.21.99/GoogleInstaller_en.application?appguid%3D%7B8A69D345-D564-463C-AFF1-A69D9E530F96%7D%26iid%3D%7B7FA73DB6-ED03-D6C1-45AB-F52270CB3208%7D%26lang%3Den%26browser%3D2%26usagestats%3D1%26appname%3DGoogle%2520Chrome%26needsadmin%3Dfalse%26brand%3DCHFX%26installdataindex%3Ddefaultbrowser has started.

ERROR DETAILS
Following errors were detected during this operation.
* [3/7/2012 5:31:46 PM] System.IO.FileNotFoundException
- The system cannot find the file specified. (Exception from HRESULT: 0x80070002)
- Source: System.Deployment
- Stack trace:
at System.Deployment.Internal.Isolation.IsolationInterop.GetUserStore(UInt32 Flags, IntPtr hToken, Guid& riid)
at System.Deployment.Application.ComponentStore..ctor(ComponentStoreType storeType, SubscriptionStore subStore)
at System.Deployment.Application.SubscriptionStore..ctor(String deployPath, String tempPath, ComponentStoreType storeType)
at System.Deployment.Application.SubscriptionStore.get_CurrentUser()
at System.Deployment.Application.ApplicationActivator.PerformDeploymentActivation(Uri activationUri, Boolean isShortcut, String textualSubId, String deploymentProviderUrlFromExtension, BrowserSettings browserSettings, String& errorPageUrl)
at System.Deployment.Application.ApplicationActivator.ActivateDeploymentWorker(Object state)

2. When I try to download a Yahoo Toolbar I get this message:

Yahoo._toolbar_install_helper.exe couldn't be downloaded.

3. When I try to download Malbytesware antimalware I get this message:

Mbam—setup-1.60.1-1000.exe couldn't be downloaded.

What can be done to resolve this problem?


Thank you