Virginia devotes a couple of chapters in the state statutes to the rights and obligations of residential tenants and landlords. The statutes have almost nothing to say about commercial renters. Generally, Virginia law follows the lease: the tenant's legal rights are the ones she negotiated in the lease agreement and that's about it.
Unlike residential leases, nothing in Virginia law obligates a landlord to maintain the tenant's premises. If it's written into the lease that the landlord provide maintenance or repairs, then he has an obligation to do so, but otherwise he has none. The terms of the lease may be very specific: if the lease obligates the landlord to maintain the air conditioning, for example, that doesn't mean he's obligated to replace it, even if it runs very poorly.
Virginia is one of several states that allow a commercial landlord to perform a "self help eviction"; rather than going to court to evict tenants, the landlord uses tactics, such as changing the locks or shutting off building utilities. The landlord must do this without causing a "breach of the peace" -- having people thrown out bodily, for example, would be illegal. A landlord should also make sure that the grounds he claims for eviction are allowed under the lease, or a court may side with the tenant.
Like the landlord's responsibility for repairs, the fate of commercial lessee's security deposits depends on what's negotiated into the lease. There are no laws governing the size of a commercial tenant's deposit, what sort of account it should be placed in or what the landlord can do with the money before settling up when the tenant leaves. The timing and the terms for returning the deposit also depend more on the lease than the law.
The best protection for a tenant is to negotiate the terms of the lease. A tenant should know what terms he wants before signing, and never sign without reading it -- even if the landlord claims it contains all the terms they agreed on. Tenants who don't have the expertise to understand the terms should hire someone who does to negotiate for them. If having the right to sublet the lease or a guarantee of prompt maintenance is important, the only way to assure such things is through the lease.